Sealing arrangement for a laser enclosure

ABSTRACT

A protective enclosure is provided for a laser system having a laser generator for generating and directing a laser beam to a laser workstation. The enclosure includes a housing having an inner cavity for containing the laser workstation. The housing further includes a section having an opening through which workpieces pass into and out of the inner cavity. The enclosure additionally includes a rotary turntable for moving the workpieces through the opening into and out of the inner cavity, and passive sealing members movably coupled to the section for sealing a portion of the rotary turntable with a portion of the section to inhibit laser energy from exiting the housing through the opening.

This is a continuation of application Ser. No. 08/113,227 filed Aug. 27,1993, now U.S. Pat. No. 5,464,963.

BACKGROUND OF THE INVENTION

The present invention relates in general to the use of industrial lasersand, more particularly, to a passive sealing arrangement for anenclosure which houses industrial lasers or like devices.

Industrial lasers are known in the prior art. Such lasers are commonlyused for purposes of welding and cutting. U.S. and internationalstandards have been developed which divide all industrial lasers intofour major hazard categories, i.e., four broad classes (I to IV). Theweakest lasers are Class I lasers which emit laser radiation below knownhazard levels. The strongest lasers are Class IV lasers which arehazardous to view under any condition (directly or diffusely scattered)and are a potential fire hazard and a skin hazard.

Laser enclosures are also known in the prior art. Such enclosures arecommonly used as protective enclosures for higher powered lasers, e.g.,Class II, Class III or Class IV lasers, and allow the higher poweredlasers to operate in a lower classification. For example, some Class Iindustrial lasers consist of a higher class laser enclosed in a properlyinterlocked and labeled protective enclosure.

One laser enclosure found in the prior art encases a laser workstation.Associated with the workstation is a laser device which acts to generateand direct a laser beam to the workstation for performing laseroperations upon workpieces that pass into the enclosure.

The noted laser enclosure comprises three stationary walls, a stationaryceiling and a fourth stationary wall having an opening through whichworkpieces pass into and out of the inner cavity of the enclosure. Theenclosure includes a rotary turntable having four vertical partitionsthat attach to a hub at the turntable's center of rotation, which iscoplanar with the fourth stationary wall. Positioned between the fourvertical partitions are four fixtures for mounting workpieces onto therotary turntable.

Portions of two of the vertical partitions are sealed to a portion ofthe fourth stationary wall by hinged flaps to inhibit the escape oflaser radiation from the enclosure. Those flaps are moved betweensealing and non-sealing positions by a plurality of pneumatic cylinders.It has been found that operation of the cylinders is time consuming,resulting in an undesirable pause occurring between laser operations.Accordingly, this active sealing arrangement is a substantial limitationon welding efficiency, especially where a succession of workpieces is tobe welded.

There is therefore a need for an improved sealing arrangement which doesnot require active drive devices, such as pneumatic cylinders, toaccomplish sealing. Furthermore, there is a need for an improved sealingarrangement which allows sealing to be accomplished in a quick andefficient manner.

SUMMARY OF THE INVENTION

These needs are met by the passive sealing arrangement of the presentinvention. The sealing arrangement forms part of a protective enclosurewhich may, for example, encase a Class IV laser to allow it to operateas a Class I laser. The protective enclosure further includes a housinghaving a section with an opening through which workpieces pass into andout of an inner cavity of the housing. Additionally provided istransport means for moving workpieces through the opening into and outof the inner cavity. The passive sealing arrangement serves to seal aportion of the transport means to a portion of the housing section toinhibit the escape of laser energy from the enclosure. The sealingarrangement of the present invention allows sealing to be accomplishedin a quick and efficient manner.

In accordance with a first aspect of the present invention, a lasersystem is provided which includes generator means for generating anddirecting a laser beam to a laser workstation. The system furtherincludes a housing having an inner cavity for containing the laserworkstation. The housing includes a section having an opening throughwhich workpieces pass into and out of the inner cavity. The laser systemadditionally includes transport means for moving the workpieces throughthe opening into and out of the inner cavity, and passive sealing meansmovably coupled to one of the section and transport means for sealing aportion of the transport means with a portion of the section to inhibitlaser energy from exiting the housing through the opening.

The housing preferably further includes first, second and thirdgenerally vertical walls, and a stationary ceiling connected to thefirst, second and third walls and the section.

The transport means may comprise a rotary turntable and a verticalpartition mounted on the rotary turntable for rotation therewith. Thevertical partition extends through the center of rotation of the rotaryturntable, which is generally coplanar with the section of the housing.

The passive sealing means may comprise first and second sealing membersand attachment means for movably mounting the first and second sealingmembers to the section. The transport means rotates between first andsecond locked positions and engages with the first and second sealingmembers as it rotates to either of its first and second locked positionsto move the first and second sealing members to a sealed position.

Preferably, the first and second sealing members each have inner andouter substantially planar surfaces. The portion of the transport meansengages with the outer surface of the first sealing member and the innersurface of the second sealing member when the transport means ispositioned in its first locked position and engages with the innersurface of the first sealing member and the outer surface of the secondsealing member when the transport means is positioned in its secondlocked position.

The attachment means preferably comprises one or more first pendulumpivot links coupled between the section of the housing and the firstsealing member and one or more second pendulum pivot links coupledbetween the section of the housing and the second sealing member. Eachof the first and second sealing members preferably comprises a beamhaving a generally I-shaped cross section. The portion of the transportmeans has a generally T-shaped cross section. The section of the housinghas a generally C-shaped cross section in order to envelop the twosealing members while permitting them to move to a sealed position.

In accordance with a second aspect of the present invention, a system isprovided for operating on a workpiece and includes a welding devicepositioned at a welding workstation. Further provided is a housinghaving an inner cavity for containing the welding workstation. Thehousing includes a section having an opening through which workpiecespass into and out of the inner cavity. The system additionally includestransport means for moving the workpieces through the opening into andout of the inner cavity, and passive sealing means pivotably coupled tothe section for sealing a portion of the transport means with a portionof the section to inhibit electromagnetic energy from exiting thehousing through the opening.

In accordance with a third aspect of the present invention, an enclosureis provided and includes a housing having an inner cavity for containinga welding workstation. The housing includes a section having an openingthrough which workpieces pass into and out of the inner cavity. Theenclosure further includes transport means for moving the workpiecesthrough the opening into and out of the inner cavity, and passivesealing means pivotably connected to the section for sealing a portionof the transport means with a portion of the section to inhibitelectromagnetic energy from exiting the housing through the opening.

Accordingly, it is an object of the present invention to provide animproved sealing arrangement for a protective enclosure. It is a furtherobject of the present invention to provide an improved protectiveenclosure for encasing a workstation. It is another object of thepresent invention to provide an improved passive sealing arrangement fora laser enclosure. It is yet another object of the present invention toprovide an improved laser-enclosure for encasing a laser workstation.These and other objects and advantages of the present invention will beapparent from the following description, the accompanying drawings andthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a protective enclosure constructed inaccordance with the present invention;

FIG. 2 is a perspective view of first and second sealing members of theenclosure shown in FIG. 1;

FIG. 3 is a front view of the enclosure of FIG. 1;

FIG. 4 is a view taken along section line 4--4 in FIG. 3, but with thependulum pivot links removed;

FIGS. 5-7 are sequential schematic illustrations without the pendulumpivot links showing the operation of the apparatus of FIG. 1;

FIG. 8 shows a lateral pendulum pivot link of the enclosure of FIG. 1;

FIG. 9 shows an upper pendulum pivot link of the enclosure of FIG. 1;

FIG. 10 is an enlarged view of a centrally located upper portion of thevertical partition, upper ends of the first and second sealing members,a downwardly extending portion on the outer panel of the front section,and an outwardly projecting blocking member on the vertical partition,which member is shown partially broken-away;

FIG. 11 is an enlarged view of the C-shaped section of the secondsealing member which defines a gap through which a downwardly extendingedge of a rotary turntable passes;

FIG. 12 is a view taken along section line 12--12 in FIG. 11;

FIG. 13 is an enlarged view of only the second lower corner extension ofthe vertical partition shown in FIG. 11;

FIG. 14 is a view taken along section line 14--14 in FIG. 13;

FIG. 15 is a schematic illustration of a portion of an enclosure formedin accordance with an alternative embodiment of the present invention;and

FIGS. 16 and 17 are schematic illustrations without the pendulum pivotlinks showing the operation of the apparatus of FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to FIG. 1, which illustrates a protective laserenclosure 10 constructed in accordance with the present invention. Theenclosure 10 includes a housing 20 having first, second and thirdgenerally vertical walls 22, 24 and 26, respectively, see also FIGS. 3and 4. A stationary ceiling 28 is fixedly connected to the first, secondand third walls 22, 24, and 26. A front channel section 30 is connectedto the first and third walls 22 and 26 and the ceiling 28. The first andthird walls 22 and 26, in the illustrated embodiment, include filteredviewing ports 22a and 26a.

The housing 20 includes an inner cavity 20a containing a laserworkstation 20b, see FIG. 4. Associated with the laser workstation 20bis a welding device 40 for cutting or welding a workpiece 20c. Thedevice 40 comprises, in the illustrated embodiment, an articulated armrobot 41 (see, e.g., U.S. Pat. No. 4,884,189, the disclosure of which ishereby incorporated by reference) having a Nd:YAG continuous wave (CW)cutting head 42, see FIG. 1. The robot 41 is controlled via a systemcontroller 44. The robot 41 is commercially available from Motoman Inc.under the trademark Motoman® K10S or K10ASB robot. The controller 44 islikewise commercially available from Motoman Inc. A fiber optic cable 46connects the cutting head 42 with a conventional Nd:YAG laser 48. Thedevice 40 may alternatively comprise any machine used in welding, suchas a CO₂ laser device or an electric-arc welding device.

The front section 30 includes an opening 32, see FIG. 3, through whichthe workpieces 20c pass into and out of the inner cavity 20a. Theopening 32 is defined by upper, side and lower edges 30a, 30b, 30c and30d of the front section 30, see also FIG. 4.

The enclosure 10 further includes a rotary turntable 52 for moving theworkpieces 20c through the opening 32 into and out of the inner cavity20a. The rotary turntable's center of rotation is generally coplanarwith the center of the front section 30. A vertical partition 54 isfixedly mounted on the turntable 52 for rotation therewith. The verticalpartition 54 extends through the center of rotation of the rotaryturntable 52, see FIG. 4. Fixtures 52a are secured on the upper surface52b of the turntable 52 for mounting the workpieces 20c to the turntable52.

The turntable 52 is adapted for approximately 180° reciprocating travelbetween first and second locked positions. A drive mechanism 56 iscoupled to the turntable 52 for rotating the turntable 52 back and forthbetween its two locked positions, see FIGS. 1 and 3. Actuation of thedrive mechanism 56 is effected by the controller 44. Two non-contactproximity sensors 70a and 70b are independently connected to two inputchannels of the controller 44 in order to confirm that the turntable 52has correctly traveled to either of its first and second lockedpositions. The two non-contact proximity sensors 70a and 70b are fixedinside the inner cavity 20a, such as to turntable base 52d, so that eachsensor 70a and 70b can detect the presence or absence of only one of twobuttons 71a and 71b. The two buttons 71a and 71b are attached to theunderside of the turntable 52 such that the second button 71b is nearerthe axis of rotation of the turntable 52 than the first button 71a, seeFIG. 1. The controller 44 only permits the processing of the workpiecesto commence if the turntable 52 has correctly traveled to either of itsfirst or second locked positions. When the turntable 52 is located inits first locked position, the button 71a will be positioned directlyacross from the sensor 70a. When the turntable 52 is located in itssecond locked position, the button 71b will be positioned directlyacross from the sensor 70b.

A lower central front portion 30e of the section 30 extends out fromfront lateral portions 30f and 30g of the section 30 to encase the drivemechanism 56 in a semicylindrical housing. A planar surface 30h isattached underneath the lower central front portion 30e to furtherencase the drive mechanism 56 and to inhibit the escape of the laserenergy from the enclosure 10.

First and second sealing members 60 and 62 are movably coupled withinthe front channel section 30 of the housing 20, see FIGS. 1-3 (thesecond sealing member 62 is not shown in FIG. 1 for clarity ofillustration). A first lateral pendulum pivot link 64a and first andsecond upper pendulum pivot links 64b and 64c are fixedly connected bybolts 65 to the first sealing member 60 and the channel section 30 formovably coupling the first sealing member 60 to the section 30. A secondlateral pendulum pivot link 66a and third and fourth upper pendulumpivot links 66b and 66c are fixedly connected by bolts 67 to the secondsealing member 62 and the channel section 30, see also FIGS. 8 and 9,for movably coupling the second sealing member 62 to the section 30.

As best shown in FIGS. 2 and 4, each of the first and second sealingmembers 60 and 62 comprises a beam having a generally I-shaped crosssection. Accordingly, the first sealing member 60 has inner and outersubstantially planar surfaces 60a and 60b, respectively, and the secondsealing member 62 has inner and outer substantially planar surfaces 62aand 62b, respectively, see FIG. 4.

The vertical partition 54 has a T-shaped outer edge 55 extending alongits first and second upper portions 54a and 54b and its first and secondside portions 54c and 54d, see FIGS. 4, 5-7 and 10. The partition 54further includes a generally planar edge 56 which extends along itscentrally located upper portion 54e, which is interposed between thefirst and second upper portions 54a and 54b. The partition 54additionally includes first and second lower corner extensions 54f and54g, each of which is integral with a downwardly extending edge 52c ofthe turntable 52, see FIGS. 11-14. Each of the extensions 54f and 54gextends out from opposite sides of and below the edge 52c of theturntable 52. The outer edge 55 extends along the first and secondcorner extensions 54f and 54g.

As the turntable 52 rotates clockwise from its second locked position toits first locked position, see FIG. 5, the outer edge 55 engages withthe outer surface 60b of the first sealing member 60 and moves the firstsealing member 60 to its first sealed position where its inner surface60a is engaged with an inner sealing edge 30h of the front section 30,see FIG. 6. Further, during rotation of the turntable 52 from its secondlocked position to its first locked position, the outer edge 55 engageswith the inner surface 62a of the second sealing member 62 and moves thesecond sealing member 62 to its first sealed position where its outersurface 62b is engaged with an outer sealing edge 30i of the frontsection 30, see FIG. 4.

When the turntable 52 rotates counterclockwise from its first lockedposition to its second locked position, the outer edge 55 engages withthe inner surface 60a of the first sealing member 60 and moves the firstsealing member 60 to its second sealed position where its outer surface60b is engaged with the outer sealing edge 30i of the front section 30,see FIG. 7. Further, as the turntable 52 is rotating to its secondlocked position, the outer edge 55 engages with the outer surface 62b ofthe second sealing member 62 and moves the second member 62 to itssecond sealed position where its inner surface 62a is engaged with theinner sealing edge 30h of the front section 30. When the sealing members60 and 62 are in one of their two sealed positions, they serve toinhibit laser energy from exiting the housing 20 through the opening 32.

The front section 30 includes inner and outer panels 31a and 31b, seeFIG. 4. As best shown in FIG. 10, the outer panel 31b has a downwardlyextending portion 30j which extends across a gap 68 positioned betweenrespective upper ends 60c and 62c of the first and second sealingmembers 60 and 62. The downwardly extending portion 30j serves toinhibit laser energy from exiting the housing 20 through the gap 68. Theinner panel 31a likewise includes a downwardly extending portion (notshown) which extends across the gap 68 between the ends 60c and 62c ofthe sealing members 60 and 62. The vertical partition 54 is providedwith an outwardly projecting blocking member 59 which is shown partiallybroken-away in FIG. 10 and serves to block laser energy which might passthrough a gap 69 positioned between the lower edge 30k of the downwardlyextending portion 30j and the edge 56 of the partition 54.

The first sealing member 60 has a lower C-shaped section 60d whichdefines a first gap 34 through which the downwardly extending edge 52cof the turntable 52 passes as the turntable 52 rotates between its firstand second locked positions, see FIGS. 2 and 3. Similarly, the secondsealing member 62 has a lower C-shaped section 62d which defines asecond gap 35 through which the downwardly extending edge 52c of theturntable 52 passes as the turntable 52 rotates between its first andsecond locked positions, see FIGS. 11 and 12. Because the generallyT-shaped outer edge 55 extends below the upper surface 52b of theturntable onto the lower corner extensions 54f and 54g of the verticalpartition 54, see FIG. 13, a proper overlap of the surfaces is createdin either of the first and second locked positions. Accordingly, a vastmajority of the laser radiation emitted within the housing 20 isprevented from escaping through the gaps 34 and 35 such that the laserdevice 40 may operate as a Class I laser.

In an alternative embodiment of the present invention, first and secondsealing members are movably coupled to the vertical partition 82 of theturntable 84 rather than to the front section 86. See FIGS. 15-17,wherein only the first sealing member 80 is shown. The first and secondsealing members are located within a peripheral recess 82a in thevertical partition 82 and are movably coupled to the vertical partition82, such as by a plurality of pendulum pivot links (not shown).

The first and second sealing members represented by the sealing member80 in FIGS. 15-17, extend along upper and side edges of the verticalpartition 82. Thus, the first and second sealing members move betweenfirst and second sealed positions, see FIGS. 17 and 16, as the turntable84 rotates between its first and second locked positions. Whenpositioned in either of its first or second sealed positions, the firstand second sealing members engage with a T-shaped edge 86a on the frontsection 86 and an edge 82b on the portion of the vertical partition 82defining the peripheral recess 82a for sealing the front section 86 tothe vertical partition 82.

With the present invention, a protective laser enclosure is provided forencasing a Class IV laser to allow it to operate as a Class I laser. Theenclosure includes an improved passive sealing arrangement comprisingfirst and second sealing members 60 and 62 which interact with thevertical partition 54 and the section 30 of the housing 20 for sealingthe partition 54 to the section 30 to inhibit an unacceptable amount oflaser energy from escaping the housing 20 through the opening 32 in thesection 30.

Having described the invention in detail and by reference to preferredembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of theinvention as defined in the appended claims.

What is claimed is:
 1. A laser system comprising:a generator for generating and directing a laser beam to a laser workstation; a housing having an inner cavity for containing said laser workstation, said housing including a section having an opening through which workpieces pass into and out of said inner cavity; a transport device for moving said workpieces through said opening into and out of said inner cavity; and, passive sealing apparatus movably coupled to one of said section and said transport device for sealing a portion of said transport device with a portion of said section to inhibit laser energy from exiting said housing through said opening.
 2. A laser system as set forth in claim 1, wherein said housing further comprises:first, second and third generally vertical walls; and a stationary ceiling connected to said first, second and third walls and said section.
 3. A laser system as set forth in claim 1, wherein said transport device comprises a rotary turntable and a vertical partition mounted on said rotary turntable for rotation therewith, said vertical partition extending through the center of said rotary turntable.
 4. A laser system as set forth in claim 1, wherein said passive sealing apparatus comprises first and second sealing members and attachment apparatus for movably mounting said first and second sealing members to said section.
 5. A laser system as set forth in claim 4, wherein said transport device rotates between first and second locked positions and engages with said first and second sealing members as it rotates to either of its first and second locked positions to move said first and second sealing members to a sealed position.
 6. A laser system as set forth in claim 5, wherein said first and second sealing members each have inner and outer substantially planar surfaces, said portion of said transport device engages with said outer surface of said first sealing member and said inner surface of said second sealing member when said transport device is positioned in its first locked position and engages with said inner surface of said first sealing member and said outer surface of said second sealing member when said transport device is positioned in its second locked position.
 7. A laser system as set forth in claim 4, wherein said attachment apparatus comprises two first pendulum pivot links coupled between said section and said first sealing member and two second pendulum pivot links coupled between said section of said housing and said second sealing member.
 8. A laser system as set forth in claim 4, wherein each of said first and second sealing members comprises a beam having a generally I-shaped cross section.
 9. A laser system as set forth in claim 4, wherein said portion of said transport device has a generally T-shaped cross section.
 10. A laser system as set forth in claim 4, wherein said transport device is adapted for 180° reciprocating travel between first and second locked positions.
 11. A system for operating on a workpiece comprising:a welding device at a welding workstation; a housing having an inner cavity for containing said welding workstation, said housing including a section having an opening through which workpieces pass into and out of said inner cavity; a transport device for moving said workpieces through said opening into and out of said inner cavity; and, passive sealing apparatus movably coupled to one of said section and said transport device for sealing a portion of said transport device with a portion of said section to inhibit electromagnetic energy from exiting said housing through said opening.
 12. A system as set forth in claim 11, wherein said housing further comprises:first, second and third generally vertical walls; and a stationary ceiling connected to said first, second and third walls and said section.
 13. A system as set forth in claim 11, wherein said transport device comprises a rotary turntable and a vertical partition mounted on said rotary turntable for rotation therewith, said vertical partition extending through the center of said rotary turntable.
 14. A system as set forth in claim 11, wherein said passive sealing apparatus comprise first and second sealing members and attachment apparatus for pivotably mounting said first and second sealing members to said section.
 15. A system as set forth in claim 14, wherein said transport device rotates between first and second locked positions and engages with said first and second sealing members as it rotates to either of its first and second locked positions to move said first and second sealing members to a sealed position.
 16. A system as set forth in claim 15, wherein said first and second sealing members each have inner and outer substantially planar surfaces, said portion of said transport device engages with said outer surface of said first sealing member and said inner surface of said second sealing member when said transport device is positioned in its first locked position and engages with said inner surface of said first sealing member and said outer surface of said second sealing member when said transport device is positioned in its second locked position.
 17. A system as set forth in claim 14, wherein said attachment apparatus comprises two first pendulum pivot links coupled between said section and said first sealing member and two second pendulum pivot links coupled between said section and said second sealing member.
 18. A system as set forth in claim 14, wherein each of said first and second sealing members comprises a beam having a generally I-shaped cross section.
 19. An enclosure comprising:a housing having an inner cavity for containing a welding workstation, said housing including a section having an opening through which workpieces pass into and out of said inner cavity; a transport device for moving said workpieces through said opening into and out of said inner cavity; and, passive sealing apparatus movably connected to one of said section and said transport device for sealing a portion of said transport device with a portion of said section to inhibit electromagnetic energy from exiting said housing through said opening.
 20. A system as set forth in claim 19, wherein said passive sealing apparatus comprises first and second sealing members and attachment apparatus for pivotably mounting said first and second sealing members to said section. 